The Terminal High Altitude Area Defense (THAAD) system is no longer about the THAAD anti-missile system. As the manufacturer states, the system may be very good at protecting specific areas such as military bases. Its range of 200km can be crucial but limited. Missile specialists say public claims about THAAD's radar by the US and China both have some validity.

For Korean political leaders the larger question has never been about the THAAD's range or utility. Rather, their assessment of any anti-missile system has been based on threats, probabilities, and various countermeasures available to meet or combat these threats. The possibility that North Korea will launch missiles at South Korea, or at particular targets within the ROK, is real. But that threat also depends on several variables. The two biggest are 1. Will the DPRK leader be willing to pay the price for launching any missile into the South? Put another way, does deterrence work? 2. Would the military, diplomatic, and strategic environment lead the North to attack the South in what would be a suicidal act? Put another way, can the root causes of threats be addressed diplomatically, thus reducing the threat?

There is a third variable for South Korean leaders. That is how the threats impact political and ideological calculations, alliance relations with the US, and roles and relationships with neighbors and partners. If one believes (incorrectly) that it was the DPRK, rather than the US, that abandoned the 1994 Agreed Framework (AF), or that North-South engagement "failed," then opposition to talks, agreements and diplomacy is more understandable. If, on the other hand, one knows it was the U.S. administration that abandoned the AF ­ and its ally ­ beginning in 2001, and it was the ROK administration that rejected inter-Korean engagement beginning in 2008, then the US-North and South-North initiatives may have been good deals. In fact, the results of sanctions and military exercises and deployments for the past 16 years are now a spectacular failure. The record of previous diplomatic agreements and follow-through looks better by comparison. Much better.

Korean security vs THAAD

If evaluated on the basis of deeper and more enduring security, THAAD's impact differs from its basic military utility. If the Korean president accepts the THAAD deployment, he will be fatally compromised by appearing to surrender foreign and security policy, flexibility, and inter-Korean relations to his disgraced predecessor, while at the same time needing to explain the decision to his nervous Chinese neighbor. For the new president to begin his term with THAAD hanging around his neck is to tie his hands before he has begun. THAAD is a good system, but it isn't worth this.

If the THAAD deployment is delayed or paused, South Korea can preserve its relations with both the US and China. With the US, there is no logical reason why Obama's THAAD deployment should be a priority for the Trump administration. Korea would be able to stress the security and military dividends that would be paid as North-South dialogue was resumed, and other initiatives were pursued. It could also ensure that U.S. military, diplomatic and commercial opportunities were protected in coming years. With China, the key point must be that its illegal economic boycott must immediately stop. No normal relations can continue until that happens. In parallel, public and private statements must make clear that China will have no impact on Korea's military decisions. Only realistic evaluation of threats will impact policy.

Test for the new president

The U.S. and South Korea have often been out of step in their policies. That is deeply worrying to specialists in both Seoul and Washington, as the next Korean president may see things differently from President Trump and his advisors. As noted in a previous column however, the bottom line is that neither the U.S. nor China is prepared to lead the next stage of initiatives with North Korea. Seoul must do it, or be buffeted about as a junior player. The worst result of early elections in May would be the election of a president who is not tough enough, inclusive enough, modest enough, or wise enough to take advantage of the current situation.

The current levels of threat are extreme largely because there have been years of pressure without serious talks. That may be about to change with a new Korean administration. Now is not the time to make conflict more likely and diplomacy more difficult by deploying THAAD.

Stephen Costello is a producer of AsiaEast, a web and broadcast-based policy roundtable focused on security, development and politics in Northeast Asia. He writes from Washington, D.C. He can be reached at scost55@gmail.com.